How does the Ivanpah solar electric generating station work? 2015

HOW DOES THE IVANPAH SOLAR ELECTRIC GENERATING STATION WORK? Ivanpah Solar's concentrated solar thermal tower technology produces electricity the same way as fossil fuel power plants: by creating high-temperature steam to turn a conventional turbine. However, instead of using fossil fuels to create steam, it uses the sun's thermal energy. Central to the technology is a solar-field design that utilizes thousands of heliostats, each consisting of two mirrors. Optimization software and a control system allow individual heliostats to track the sun in two dimensions, thereby reflecting sunlight to a boiler positioned atop a tower. When concentrated sunlight strikes the solar receiver, it heats water to create superheated steam, which is piped down from the boiler to a conventional steam turbine that generates electricity. Transmission lines then carry the power to homes and businesses in Southern California. INFORMATION • Located on 14.2 square kilometers (about 5.5 square miles) of public land, managed by the US Bureau of Land Management • Three-unit power tower system capacity: 377 megawatts (Net) / 392 megawatts (Gross) Unit 1: 126 megawatts Unit 2: 133 megawatts Unit 3: 133 megawatts • Tower Height: 140 meters (459 feet) • Number of Heliostats: 173,500 (2 mirrors per heliostat) • Reflective Area per Heliostat: 15.2 square meters (a little over 163 square feet) • Heliostat Solar-Field Aperture Area: 2,637,200 square meters (28,386,585 square feet; about 2.5 square kilometers or 1 square mile) • Average Homes Served Annually: 140,000 • Average Heliostat Installation Rate: 1 per minute during construction period • Heliostat Placement Accuracy: +/- 10 centimeters (4 inches) of depth; 15 centimeters (6 inches) of leeway in location • Boiler Type: Solar Receiver Steam Generator (SRSG) • Cooling Method: Dry (air-cooled condenser) • Water Consumption: 123,000 cubic meters per year (100 acre feet per year), equivalent to 300 homes per year • Avoided Emissions: More than 400,000 metric tons of carbon dioxide (CO2) each year • Construction Jobs Created: More than 2,100 craft workers, a total of 2,636 workers at peak construction • Owners: NRG Energy, Google, and BrightSource Energy • EPC Contractor: Bechtel • Customers: Pacific Gas & Electric; Southern California Edison • Construction Commenced: October 2010 • Operational: December 2013